With the increasing down scaling of integrated circuits and increasingly higher requirements for integrated circuits, transistors need to have higher drive currents with increasingly smaller dimensions. Fin field-effect transistors (FinFET) were thus developed. The FinFETs have increased channel widths, which channels include the portions formed on the sidewalls of the fins and the portions on the top surface of the fins. Since the drive currents of transistors are proportional to the channel widths, the drive currents are increased.
Similar to a planar transistor, source and drain silicides may be formed on the source and drain regions of FinFETs. FIG. 1 illustrates a cross-sectional view of a source/drain region of a FinFET. The source/drain region includes fin 20, epitaxial semiconductor regions 22, and silicide layer 24. It is noted that silicide layer 24 is mainly formed on the top of fin 20 and epitaxial semiconductor regions 22, and thickness T1 of the portion of silicide layer 24 on the top of fin 20 and epitaxial semiconductor regions 22 is significantly greater than thickness T2 on the sidewalls of epitaxial semiconductor regions 22. Some portions of the sidewalls of epitaxial semiconductor regions 22 may even be substantially free from silicide layer 24. Such a profile may adversely cause the increase in current crowding. Further, the effective source/drain resistance is also increased.